Television channels and stations established in 1965

Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, entertainment, news, and sports.

Television became available in crude experimental forms in the late 1920s, but only after several years of further development was the new technology marketed to consumers. After World War II, an improved form of black-and-white television broadcasting became popular in the United Kingdom and the United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion.Diggs-Brown, Barbara (2011
''Strategic Public Relations: Audience Focused Practice''
p. 48 In the mid-1960s, color broadcasting was introduced in the U.S. and most other developed countries.

The availability of various types of archival storage media such as Betamax and VHS tapes, LaserDiscs, high-capacity hard disk drives, CDs, DVDs, flash drives, high-definition HD DVDs and Blu-ray Discs, and cloud digital video recorders has enabled viewers to watch pre-recorded material—such as movies—at home on their own time schedule. For many reasons, especially the convenience of remote retrieval, the storage of television and video programming now also occurs on the cloud (such as the video-on-demand service by Netflix). At the end of the first decade of the 2000s, digital television transmissions greatly increased in popularity. Another development was the move from standard-definition television (SDTV) ( 576i, with 576 interlaced lines of resolution and 480i) to high-definition television (HDTV), which provides a resolution that is substantially higher. HDTV may be transmitted in different formats: 1080p, 1080i and 720p. Since 2010, with the invention of smart television, Internet television has increased the availability of television programs and movies via the Internet through streaming video services such as Netflix, Amazon Prime Video, iPlayer and Hulu.

In 2013, 79% of the world's households owned a television set. The replacement of earlier cathode-ray tube (CRT) screen displays with compact, energy-efficient, flat-panel alternative technologies such as LCDs (both fluorescent-backlit and LED), OLED displays, and plasma displays was a hardware revolution that began with computer monitors in the late 1990s. Most television sets sold in the 2000s were flat-panel, mainly LEDs. Major manufacturers announced the discontinuation of CRT, Digital Light Processing (DLP), plasma, and even fluorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are expected to be gradually replaced by OLEDs. Also, major manufacturers have announced that they will increasingly produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s.

Television signals were initially distributed only as terrestrial television using high-powered radio-frequency television transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by coaxial cable or optical fiber, satellite systems and, since the 2000s via the Internet. Until the early 2000s, these were transmitted as analog signals, but a transition to digital television was expected to be completed worldwide by the late 2010s. A standard television set consists of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is correctly called a video monitor rather than a television.

Etymology

The word ''television'' comes . The first documented usage of the term dates back to 1900, when the Russian scientist Constantin Perskyi used it in a paper that he presented in French at the first International Congress of Electricity, which ran from 18 to 25 August 1900 during the International World Fair in Paris.

The anglicised version of the term is first attested in 1907, when it was still "...a theoretical system to transmit moving images over telegraph or telephone wires". It was "...formed in English or borrowed from French ." In the 19th century and early 20th century, other "...proposals for the name of a then-hypothetical technology for sending pictures over distance were telephote (1880) and televista (1904)."

The abbreviation ''TV'' is from 1948. The use of the term to mean "a television set" dates from 1941. The use of the term to mean "television as a medium" dates from 1927.

The slang term ''telly'' is more common in the UK. The slang term "the tube" or the "boob tube" derives from the bulky cathode-ray tube used on most TVs until the advent of flat-screen TVs. Another slang term for the TV is "idiot box".

Also, in the 1940s and throughout the 1950s, during the early rapid growth of television programming and television set ownership in the United States, another slang term became widely used in that period and continues to be used today to distinguish productions originally created for broadcast on television from films developed for presentation in movie theaters.Johnson, Richard (2018)
“Big movie stars are not making the cut on the small screen”
p. 6, ''The New York Post'', 11 October 2018. Retrieved 24 November 2018. The "small screen", as both a compound adjective and noun, became specific references to television, while the " big screen" was used to identify productions made for theatrical release.

History

Mechanical

Facsimile transmission systems for still photographs pioneered methods of mechanical scanning of images in the early 19th century. Alexander Bain introduced the facsimile machine between 1843 and 1846. Frederick Bakewell demonstrated a working laboratory version in 1851. Willoughby Smith discovered the photoconductivity of the element selenium in 1873. As a 23-year-old German university student, Paul Julius Gottlieb Nipkow proposed and patented the Nipkow disk in 1884. This was a spinning disk with a spiral pattern of holes in it, so each hole scanned a line of the image. Although he never built a working model of the system, variations of Nipkow's spinning-disk " image rasterizer" became exceedingly common. Constantin Perskyi had coined the word ''television'' in a paper read to the International Electricity Congress at the International World Fair in Paris on 24 August 1900. Perskyi's paper reviewed the existing electromechanical technologies, mentioning the work of Nipkow and others. However, it was not until 1907 that developments in amplification tube technology by Lee de Forest and Arthur Korn, among others, made the design practical."Sending Photographs by Telegraph"
''The New York Times'', Sunday Magazine, 20 September 1907, p. 7.

The first demonstration of the live transmission of images was by Georges Rignoux and A. Fournier in Paris in 1909. A matrix of 64 selenium cells, individually wired to a mechanical commutator, served as an electronic retina. In the receiver, a type of Kerr cell modulated the light and a series of differently angled mirrors attached to the edge of a rotating disc scanned the modulated beam onto the display screen. A separate circuit regulated synchronization. The 8x8 pixel resolution in this proof-of-concept demonstration was just sufficient to clearly transmit individual letters of the alphabet. An updated image was transmitted "several times" each second.

In 1911, Boris Rosing and his student Vladimir Zworykin created a system that used a mechanical mirror-drum scanner to transmit, in Zworykin's words, "very crude images" over wires to the "Braun tube" ( cathode-ray tube or "CRT") in the receiver. Moving images were not possible because, in the scanner: "the sensitivity was not enough and the selenium cell was very laggy".

In 1921, Edouard Belin sent the first image via radio waves with his belinograph.

By the 1920s, when amplification made television practical, Scottish inventor John Logie Baird employed the Nipkow disk in his prototype video systems. On 25 March 1925, Baird gave the first public demonstration of televised silhouette images in motion, at Selfridges's department store in London. Since human faces had inadequate contrast to show up on his primitive system, he televised a ventriloquist's dummy named "Stooky Bill", whose painted face had higher contrast, talking and moving. By 26 January 1926, he had demonstrated the transmission of an image of a face in motion by radio. This is widely regarded as the world's first public television demonstration. Baird's system used the Nipkow disk for both scanning the image and displaying it. A brightly illuminated subject was placed in front of a spinning Nipkow disk set with lenses which swept images across a static photocell. The thallium sulphide (Thalofide) cell, developed by Theodore Case in the U.S., detected the light reflected from the subject and converted it into a proportional electrical signal. This was transmitted by AM radio waves to a receiver unit, where the video signal was applied to a neon light behind a second Nipkow disk rotating synchronized with the first. The brightness of the neon lamp was varied in proportion to the brightness of each spot on the image. As each hole in the disk passed by, one scan line of the image was reproduced. Baird's disk had 30 holes, producing an image with only 30 scan lines, just enough to recognize a human face. In 1927, Baird transmitted a signal over of telephone line between London and Glasgow.

In 1928, Baird's company (Baird Television Development Company/Cinema Television) broadcast the first transatlantic television signal, between London and New York, and the first shore-to-ship transmission. In 1929, he became involved in the first experimental mechanical television service in Germany. In November of the same year, Baird and Bernard Natan of Pathé established France's first television company, Télévision- Baird-Natan. In 1931, he made the first outdoor remote broadcast, of The Derby. In 1932, he demonstrated ultra-short wave television. Baird's mechanical system reached a peak of 240-lines of resolution on BBC
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